Drill



N. C. KING.

DRILL.

APPLICATION FILED JUNE 13. 1021.

Patented May 16, 1922.

ATTbRNEY WITNESS:

flare-ear.

- useful Improvements in Drills,

NORMAN C. KING, '0]? DUIBOIS, PENNSYLVANIA.

DRILL.

Application filed June 13,

the reception of a cartridge for blasting purposes and has for its object the provision of a drill head' 'adapte'd for engagement upon the end of a s'uitable rod wherebyit may be rotated to effect the necessary cutting action, the device being provided with a plurality of cutting blades whereby gouging will be prevented and a formed.

An important object is the provision of a drill head carrying a plurality of removable and interchangeable blades whereby in the event of breakage a blade may be quickly and easily replaced and whereby the blades when dull may be replaced with other which have been sharpened so that a great saving in time and labor will be effected.

An additional object is the provision of a device of this character which will be simple and inexpensive in manufacture, highly efiicient in use, durable in service, and a general improvement in the art.

With the above and other objects and advantages in View, the invention consists in the details of construction to be hereinafter more fully described and claimed and illus trated in the accompanying drawings in which Figure 1 is a side elevation of my device showing a fragment of a drill rod associated therewith,

Figure 2 is a longitudinal sectional view,

Figure 3 is an end View, and

Figure 4 is a cross sectional view.

Referring more particularly to the drawings, the letter A designates a flattened end of a suitable drill rod upon which my device is carried. My device comprises a body 10 formed of suit-able material and which may preferably be a malleable casting and this body is formed at one end with a rectangular socket 11 engageable upon the end A of the rod and provided with transverse holes 12 for the passage of a suitable bolt 13 for securing the device upon the rod. The body 10 is of a somewhat auger-like shape, that to say it is formed with a pl11.-

Specification of Letters Patent.

portions with radial a central threaded hole 16. The

includes a which defines a shoulder 22.

smooth out hole will be" Patented May is, was. 1921. Serial No. 477,292

rality, preferably I four, of more or less spiral ribs 1% which are formed at their end slots 15 leading from ribs are likewise formed with passages 17 leadin from the slots 15 to the outside edges of the ribs, the passages being parallel with the hole 16.

In order to provide cutting means I make use ofal plurality of bits 18 each of which curved blade 19 having a cutting edge 20 and formed with an extension 21 The blades are associated with the body by inserting the extensions 21 thereof within the passages 17 with the shoulders 22 engaging against the bottoms of the slots 15. This holds the blades rigidly in position and from any displacement other than longitudinal. Threaded into the hole 16 is a screw 23 having an enlarged head 24 engaging against the laterally projecting innermost portions 25 of the blades whereby to hold the blades against any longitudinal displacement.

In the use of the device it will be seen that it is rotated by means of the rod A by any suitable instrumentality whereupon the cutting edges 21 of the blades will operate to dig away the material and form the desired hole. It is to be observed that the outermost edges of the blade are curved outwardly so as to out a hole of greater diameter than the maximum. width of the body and thereby prevent any possible tightening of the tool within the hole.

In the event of breakage of the blade or in the event that the blades become dull, in order to remove one or more of the blades, it is merely necessary that the operator unscrew the screw 23 and remove it, whereupon any one or all of the blades may be removed. If a blade fits so snugly that removal by the fingers is impossible it is merely necessary that the operator insert a blunt punch or other instrument within the passage 17 into which extends the extension 21 of the blade which is stuck, and apply a slight blow to such blunt instrument by means of any suitable object to force out the blade, whereupon the blade thus removed, may be easily replaced by another.

From the foregoing description and a study of the drawings it will be apparent that I have thus provided a simply constructed and consequently inexpensive drill including a plurality of bits which will insure the prevents them formation of a smooth bored hole which will greatly facilitate the insertion of the usual cartridge employed in blasting. It will also be apparent that the device will be a great time and labor saver inasmuch as a broken or dull blade or all or": the blades when dull may be easily removed and replaced in a very short time.

While I have shown and described the preferred embodiment of my invention, it is of course to be understood that I reserve the right to make such changes in the form, construction and arrangement of parts as will not depart from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention, I claim:'

1. A device of the character described comprising a body provided at one end with means for connection with a drill rod and provided at its other end with a plurality of radial slots and passages communicating with said slots, the body being provided in its end with a threaded hole communicating with said slots, a plurality of blades engaged within said slots and formed with extensions fitting within said passages, and a screw threaded into said hole and having a head engaging said blades.

2. A device of the character described comprising a body provided at one end with a socket engageable upon the drill rod and provided at its opposite end with a central threaded hole, said body including a plurality of spirally arranged ribs, the ends of said ribs at the second mentioned end of the body being. formed with radial. slots communicating with said threaded hole and the ribs being formed with longitudinal passages leadlng into said slots, and a plurality of blades corresponding to the number of ribs and each formed with an extension fitting within a passage and having its body portion seating within a slot, the

blades being formed at their inner edges with lateral extensions extending to the threaded hole, and a screw engaged withinsaid hole and having a head engaging said lateral extensions.

In testimony whereof I affix my signature.

NORMAN C. KING. 

